| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem wherein when a shearing interferometer is used for a measurement of an EUV optical system in order to utilize its advantage, tilt wave front cannot be measured, which is a need in the measurement of the EUV optical system. SOLUTION: In the shearing interferometer using diffraction gratings, two or more kinds of diffraction gratings which have the same operating wavelength and different pitches, and at least one kind of diffraction grating which has an operating wavelength differing from the same operating wavelength, are made up on their common substrate or support body. COPYRIGHT: (C)2006,JPO&NCIPI
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